Does anyone know of a depletion mode mosfet suitable for use in a 2mA ccs capable of handling 350V ?
I have use the LND150 very successfully for currents < 1mA, and the DN2540 / IXCP10M45s for currents > 7mA.
1mA appears to be the upper limit for the LND150.
The DN2540 datasheet indicates that gm is miniscule at 2mA, implying low effective resistance.
Althought the IXCP10M45 datasheet implies an operational current bandwith commencing at 2mA, I suspect that effective gm will also be very low at this current.
ideas / comments ?
I have use the LND150 very successfully for currents < 1mA, and the DN2540 / IXCP10M45s for currents > 7mA.
1mA appears to be the upper limit for the LND150.
The DN2540 datasheet indicates that gm is miniscule at 2mA, implying low effective resistance.
Althought the IXCP10M45 datasheet implies an operational current bandwith commencing at 2mA, I suspect that effective gm will also be very low at this current.
ideas / comments ?
David Davenport said:Do you think that you could use two of the LND150 in parallel?
Dave
Or try the DN3545N3. At 2 mA, you'll be able to get a significant value for the set resistor which will improve the performance.
cheers,
Douglas
Thanks guys,
I have used the DN3545 before as the lower element in a cascode with the DN2540. Surprisingly, it has a very similar current v transconductance characteristics to the DN2540 (ie it is also miniscule at 2mA), which pretty well rules it out in terms of the resultant ccs effective resistance.
The paralleling of LND150 sounds like a great idea (why didn't I think of it?) which I will definitely trial.
I have used the DN3545 before as the lower element in a cascode with the DN2540. Surprisingly, it has a very similar current v transconductance characteristics to the DN2540 (ie it is also miniscule at 2mA), which pretty well rules it out in terms of the resultant ccs effective resistance.
The paralleling of LND150 sounds like a great idea (why didn't I think of it?) which I will definitely trial.
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